A mobile phone often incorporates an auxiliary antenna in addition to a main antenna. Normally, the main antenna is used for communications. In contrast, the auxiliary antenna is used instead of the main antenna when, for example, the main antenna happens to be covered by the mobile phone user's hand supporting the mobile phone casing and thereby causing deterioration of the reception conditions. Thus, good communication conditions are maintained for the mobile phone. As such, the mobile phone is able to select one antenna from a plurality of antennas for use in communications, switching to another antenna whenever reception conditions deteriorate. This is termed a diversity function.
In a conventional mobile phone, the main antenna and the auxiliary antenna are disposed within the casing at positions as far apart as possible. This is done to enhance the effect of the diversity function. For example, when the main antenna is disposed in the vicinity of the earphone unit, the auxiliary antenna is disposed near the mouthpiece unit or, if the mobile phone is a clamshell, near the hinge. This reduces the chances of the user's hand coming to simultaneously cover both the main antenna and the auxiliary antenna.